In China, Asia’s longest river, the Yangtze, saw record low levels last month and hydroelectric power stations along its course had to reduce or stop operations, causing power outages for millions of people. This is just one of the river-related impacts of the increasingly frequent and severe dry periods which we have been seeing all over the world in 2022.
Over the past five years, one in five river basins have experienced fluctuations in surface water outside their natural range. At the same time, rivers across South Asia are swelling due to rises in rainfall and accelerated glacial melt – with devastating impacts seen most recently in Pakistan.
While rivers make up a tiny fraction (0.49 per cent) of surface fresh water, they play a large role in their support of life on Earth and human development. Of all the world’s liquid surface fresh water, 87 per cent is contained in lakes, 11 per cent in swamps, and only 2 per cent in rivers.
World Rivers Day on 25 September is an opportunity to reflect on the role rivers have played in human civilization, the pressures they face today in a world of nearly eight billion people, and the need to protect and manage them sustainably.
Here are four reasons why protecting river systems is critical:
Rivers support people and economies
Rivers are highly diverse and productive ecosystems, contributing to economic growth, food security and human well-being. Globally, an estimated 2 billion people rely directly on rivers for their drinking water and 500 million people (approximately one in 14 people on Earth) live on deltas that are sustained by sediment from rivers, according to the World Wildlife Fund (WWF).
Meanwhile, rivers provide some of the world’s most productive fisheries and livelihoods for 60 million people, 55 per cent of whom are women. At least 12 million tons of freshwater fish are caught each year (accounting for some 12 per cent of the world’s entire fish catch) – this is sufficient to provide protein for at least 160 million people, but very few decision-makers fully appreciate this value of freshwater fish. This is due to a lack of understanding or measurement of the extent to which this supports low-income communities or boosts economies.
Most of the oldest cities in the world developed around rivers which allow the transport of goods and people; support fisheries and agriculture; and provide recreational, tourism, mental health, and cultural benefits: for instance, sacred sites are found at the confluence of rivers throughout the Himalayan region, while the Ganges River and River Jordan themselves hold significant, intrinsic religious value.
The Hindu Kush Himalaya is also the source of ten of Asia’s largest river systems, as well as the main source of freshwater in South Asia. Ecosystem services from here sustain an estimated 240 million people in the region and benefit some 1.7 billion people in downstream river basins. There is an energy component to rivers –hydropower uses river water to produce electricity. At the same time rivers can also be a source of conflict between nations.
Most of our biggest rivers are badly polluted
Around one third of all rivers in Latin America, Africa, and Asia suffer from severe pathogenic pollution, which can lead to disease, and is attributed to untreated wastewater disposal, agricultural pesticides run-off and industrial pollution; severe organic pollution is found in around one seventh of all rivers; and severe and moderate salinity pollution in around one tenth of all rivers, according to the United Nations Environment Programme (UNEP).
Rivers are also suffering due to the growing scourge of plastic pollution. UNEP research shows that about 1,500 tons of microplastics per year from personal care products are estimated to escape from wastewater treatment plants into aquatic environments. A thousand rivers account for nearly 80 per cent of global annual riverine plastic emissions, which range between 0.8 million and 2.7 million tons per year, with small urban rivers among the most polluting.
Together, such widespread pollution risks the health of people, the freshwater fishing industry (threatening food security and livelihoods) and the use of river water for irrigation, industry and recreation. This pollution also ends up in the ocean with further adverse impacts.
Free-flowing rivers are few and far between
Few rivers have been left in their natural, wild, meandering state. Growing demand for hydropower, irrigation and inland navigation is driving rapid expansion of dam building and other river infrastructure, disrupting and fragmenting rivers.
Just one-third of the world’s longest rivers remain free-flowing, mostly in remote regions of the Arctic and in the Amazon and Congo basins. Infrastructure development in river floodplains can aggravate urban flooding. According to UNEP’s flagship report, Making Peace With Nature, nature-based adaptation actions can help reduce river flooding and better protect these valuable ecosystems. They include protecting and restoring floodplains and riparian vegetation.
Rivers support biodiversity
Infrastructure on rivers adversely affects aquatic life. For example, it can prevent some species of fish, such as salmon, from reaching their breeding grounds upstream. By protecting and restoring our rivers, we play a critical role in bending the biodiversity curve. Rivers and the waters and nutrients they carry feed forests, wetlands and other terrestrial habitats, and are home to many of the more than 100,000 freshwater species, according to WWF. Cleaner rivers allow nature to bounce back: porpoises are returning to the River Thames, and dolphins to the River Hooghly, a distributary of the Ganges, due to reduced industrial activity and pollution during the COVID-19 lockdowns.
UNEP is partnering with Rotary International on the Adopt a River for Sustainable Development intiative, which aims to catalyse action in local communities. Leveraging the global reach of Rotary’s more than 46,000 clubs, the initiative seeks to raise awareness of the importance of rivers and scale up action to restore and protect them. Adopt-a-River’s one-year pilot phase was completed at the end of 2021.
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